Allen’s Law – Allen Artificial Parthenogenesis – Loeb Axial Gradient theory – Child Bergman’s Rule – Bergman Biogenetic Law – Earnst Haeckel (1868) Biological Species Concept – Earnst Mayer Biogenesis Theory – Developed by F. Redi Chromosomal Theory of Inheritance – Sutton and Boveri Theory of natural selection – Charles Darwin